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Finding the Fourth Proportional to 21.81, 29.84 and 21.72

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Solution

The fourth proportional to 21.81, 29.84 and 21.72 is: 29.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.81 : 29.84 = 21.72 : x
  2. Step 2: Convert to fraction form
    21.81/29.84 = 21.72/x
  3. Step 3: Cross multiply
    21.81x = 29.84 × 21.72
  4. Step 4: Simplify right side
    21.81x = 648.02
  5. Step 5: Solve for x
    x = 648.02/21.81
  6. Step 6: Final answer
    x = 29.71

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.